Electric knife switch



Sept. 13, 1949. J. E. DIGMAN ETAL ELECTRIC KNIFE SWITCH .Filed NOV. 7,1947 FIG. 1.

IN V EN TOR.

Ww e' m *W ,4 TTORIVE vs.

Patented Sept. 13, 1949 TED; Y STATES oeeice 101m E. 'Di gman, TakomaPark, andCarl S. "Davis,

West Hyattsville,

enpheaeonmvember v, ifli iais f al heathen 2 Claims. 1

Our invention relates to dielectric switches, and

more particularly to switches ;of the knife type wherein a pivotal bladecontactis privoted into and .outiof engagement with a stationary contactto open and close a circuit, and wherein pivot means and a jouma1therefor pivotally mount said bladeand arerin said switchcircuit.

;eventually-resultinzlooseness of'the pivot which in turn leadstocorrosion ofthe contacting surfaces, a poor electrical contact,and mayeven result .insparking. Obviously, ,s parking :is a particularlydangerous fire hazard, especiallywhenthe switch is used in a motorvehicle, as aforesaid, wherein it will usually be located beneath'thehood-of the vehicle ad acent :the-batteryand-engine.

With the vfcizegoing in vi w. an object of our invention is to providean improved switch of {the class described.

A further oloject is to provide an improved switch -of the class desribed whi h includesv spring .means loadingithe pivot or shaft for theblade contact in radial and/or axial direct ons whereby to maintain anintimate, self-cleaning o c :hetween said -.shaft and. sa d journal atall times.

A iiurthe r Ohifififlfis :to provid an im v switch such as that:laat.des.crihed, wherein h st ionary -;contaot eompizises: spri g me nsasso- .ciated therewith and, hearin a ainst the itch blade in -.a.dii'eqtiqn radia y of :said: sha w er by to load the ameasafpresaid.

th Ob ects and advanta es reside in th P rticular structure- ;of :thedevic omb nati and; arrangement otthe several, parts thereof,. an.willhereadiiyiappaizenttoithosee illedjinvthea it upon reference to:the attached draw ngs in co nection with the ifoilowin specificati nwherein the inventiomisrshown, .siescribed and-claimed- In'vthedrawings:

Figure :.1is.azfiaem ntaryl n itudinal vertica section through .a motorvehicl ;..show n a prefanned use iQf ;a switch accordin ;.to ourinvention;

"Figure '2 :is an elevation on an enlar ed scale ofaswitchaeccrdingatoethe;invention;

E eur 3.. pla vi w Ithereni; i ure 4 s a t ansv rse v ttical section tasubs antially the ,n 'ane .of the lin .4.4 of

Fi ur 3;

Ftieur fi is/a l ngitudinal ertical section taken rsubstantialiy on th pane of the line .5. -5 of Fi ure 3...

In the drawings. whet in l e ,Iefereht h --ao.t rs ha e heen usedthroughout to desi na like parts, l ila iesienates Ea hemev o a mo o vhicl which includes a stora b ttery II havinga s onndeahlelli lhe'b te yH i m ted inanysuitah eoriisnalimanne adia th pa tition l3 ,sepatatine-1ihe..eng ine compartment of the vehicl i Q the hasseneer com artm n11he=switch accor atohtheinven on nc .a eulostant a iy l-vshaned brackethav n a vertical y-disposed log J 4 ethieh s nitably apertnred, a a 15,lfo attaehmentrtothe p t t on 3 o any othe sui able portion o i h vehi jcent the battery H. The braclgetaforesaid includes a hori ontaly-disposed arm 16.0 which th sw tch ac o d ng tprt h hivent oni m u tedinany Suitabl inannehas w lliappea late e upper surf-at o .the,.ho izota harm i of h Jo oket s gDl'QfliQQWith a reiat lv h ck s ee 10f su a ngmateria llon whi ism nn the lb lnlate nl3rotahicathat whi h eenera11yini ated-hy J9- :Theih aehe ma com rise a pair u an nlieeaznwhioh-areiiorm d ,withrlatorally-a gne iane turesll an 2: whichprovide ;Journa s iio a piv te eha 23 .for the pivotal aotizi. litrhouldfhehoteda t i ime that o e of h z at enin.gs 1, $2. i th s ins ancthe on en ng is smalle than the on e i g Z- v n that the shaft ale-ha hred ced re te iir25 .p nean-ahnuta csh nl erittherearouhd,w i mayseattaeainstethe inner -sii a eo th .20 fz e iournaleor asisehownimEigureA, may be op rat v to (fo e :a tthrii t washe 21 int intimate-ieaeemen with the inne surfa e o the e mic-ti he Journal. r lheniree endo t redu e end 1 5 of th ehatt ii-3 {ext n outwardly beyond th aciiae ntl g 29 and has .a sp in 28 concent ica ly d enose ga onti h sam On -rofz hfi am e "i hate aga n theoutensiiri o of th lee sill-awhile theaher :end bea aeain anyeuitahieami rnenMa eeta hahiy se uresio-n theireeendof. ther need noitio 5- h opposite end ofi he afti; extend outwardlvbyond the a.dia en flea Q who tatkot Hi, and ha :fix dthoteonnever mnd-ii- ".Fh tr e ndo the lever a ms lma ibemito ed ;:a 3. 3 t a ysuitable aotnating means it! touch a lflox ble cable, whieht'ie@Qfifittfidu h ex ncied thr ugh the partition l3 and operatively securedon the dashboard 32 for convenient operation by the driver of thevehicle.

Any suitable mounting means for the flexible cable 3| may be associatedwith the bracket for the switch, and such means may comprise a sleeve 33carried by the under surface of an ear 34 which extends laterally of thehorizontal leg l6.of the bracket. The sleeve 33 may be detachablysecured to the under surface of the ear 34 in any suitable manner, as bythe bolts 35. It is to be understood 7 from the foregoing that as theinvention is disclosed, the operator of the car upon pushing in on theactuating button 36 adjacent the dashboard 32 will be effective todepress the lever 29, whereby the shaft 23 is rotated in a clockwisedirection, Figure 2, and the blade contact 24 is raised out of contactwith the stationary contacts, to be described later.

The legs 20 for the bracket l9 are connected in vertically-spacedrelation to the base plate l8 by a cross-piece 31 which is provided onits upper surface with a vertically-extending threaded stud 38 on whicha nut 39 is threaded, whereby to clamp the free end 40 of the batteryground cable 12 thereto. The base plate '18 for the bracket I9 isdetachably secured atop the insula n Slab l1 and to the bracket arm ISin any suitable manner, such as by bolts 43 which are suitably insulatedfrom both the base plate and the horizontal arm It in any suitablemanner, as by the sleeves and/ or washers 44 and 45. The free end of thehorizontal arm I6 of the mounting bracket is provided with a threadedhorizontally-extending stud 46 and nuts 41 for'detachably securing thefree end 48 of an auxiliary ground cable 49 thereto. The opposite end ofthe auxiliary cable 49 is detachably secured, as at 50, in any suitablemanner to .the frame In of the vehicle, whereby to ground the battery llwhen the switch according to the invention is closed.

The device according to the invention comprises a pair of stationarycontacts, one of which may comprise a vertically-extending standardwhich may be clampedto the free end of the horizontal arm [6 of themounting bracket, as by the nuts 41. The upper end of the standard 5| isformed to provide a bight 52 which merges into a depending contact leaf53. Such leaf 53 is preferably a spring leaf and the spring load thereofis preferably increased by interposing a coil spring 54 between theadjacent surfaces of the leaf 53 and standard 5|. Suitable aligned pinsmay be formed on the adjacent surfaces of the standard and leaf tomaintain the spring 54 in position thereon. The outer surface of theleaf 53 is preferablyformed with a recess 55 therein which is adapted toreceive the rounded free end 55 of the pivotal blade 24 of the switch.It follows' from' the foregoing that when the switch blade 24 is movedto the closed position, Figures 2 and 5, the spring-loaded leaf 53 ofthe stationary contact will load the switch arm 24 in a directionradially of the shaft 23, whereby the shaft is forced into intimatecontact with the journals 2| and 22 of the legs of the bracket l9. Thus,the spring leaf 53 and the spring 28 load the shaft 23 in both axial andradial directions into intimate contact with the journals. It follows,then, that irrespective of wear between the axle or shaft 23 and thejournals 2| and 22, such wear will be taken up by the action of thesprings 28 and 54, together with the spring leaf 53. In this way, notonly is looseness in the shaft and journal prevented, but sparking iseliminated, and the constant pressure of the 4 springs in directions atright angles to each other against the journal tends to make the journalconnection self-cleanin whereby each actuation of the shaft 23 will beoperative to rub off any shaft and the journals.

The bracket arm [6 also mounts a pair of opposed stationarycontacts'fifl which are each inwardly spaced from a pair of bracketgears61 carried by the horizontal bracket arm |6.' Springs 62 are interposedbetween the inner surfaces of the bracket ears 6| and the-outer surfacesof the contacts 60, whereby to load the contacts 60 toward each otherand insure an intimate engagement with the adjacent portions of theswitch plate 24 as the same passes therebetween. The springs -62 may besupported in any suitable manner, as on stub pins which are fixed inaxial alignment on the opposed outer and inner surfaces of the contacts60 and ea rs 5!, respectively. Such contacts 50 cooperate with the:contact provided by the leaf spring '53' to insure a the switch isclosed. 7

The clevis 63 and pivot 35;Which connects the flexible cable. 3l to theswitch lever arm '29, is insulated from the free end of such lever armby any suitable means, such as a flanged insulating sleeve fi land aninsulating washer 65,- Figure- 3. I

:In the operation of the device, when the driver or owner of the vehiclewishes to leave the same,

and at the same time wishes to open all circuits in the vehic1e,it isonly necessary for'him to push in on the operating, handle or button36,whereby motion is transmitted through the flexible shaft 3|. to theleverarm '29. This motion is effective to give the shaft 23 a partialrotation in a clockwise. direction, when viewed as in Figure 2. to

raise the arm out of contactwith the stationary 7 contacts 53 and 60,-:whereby to open all cir'cuits'in the vehicle. At thesame timefthecrosspiece 31 of the bracket [91s efiective to engage the uppersurface of theswitch blade 24 to limit movement thereof in an open direction. Whenthedriver or owner of the vehicle wishes to use the same, he need only pullout on the handle or but ton 36,, whereby the shaft 23 is rotatedreversely to close the switch." 7

While We have shown and described what is now thought to be thepreferred embodiment of the invention, it is to "be understood that thesame is susceptiblebf other forms and expres sions. Consequently,wedonot limit'ourselves to the precise structure shown and describedhereinabove except as hereinafter claimed.

We claim: t n 1 Y 1. In combinationwithfa'pair' of "stationary side'contactsand "a stationary "U -shaped sprin leaf end contact providedwith a curved recess in the free extremity thereof, a pivotal switchblade movable into and but of engagement with said stationary contacts,an arcuate extremityon" said blade adapted to be seated in the recessin'th'e end contact when the switch is inclose d 'position, spring meanscarried bythe end contact for exerting axial pressure against the switchblade, spring means carried by each of the side contacts for excitingopposed lateral pressureagainst the switch blade, spring means carriedon the pivot of the switch blade for exerting radial pressure againstsaid blade, and an arm for actuating said switch rigidly secured to theswitch blade pivot anlh having a remote'control connected there W1 T 2.An electrical switch'compris'ing a pair of op- 75 posed stationary sidecontacts,a stationary -U+ corrosion formed on the abutting surfaces ofthe good contact when shaped spring leaf end contact transverselydisposed with respect to said side contacts, a free inner extremity onsaid end contact, an amuate recess in :the free extremity, a pivotalswitch blade movable into and out of engagement with said stationarycontacts, an arcuate extremity on the free end of said blade adapted tobe seated in the recess in the end contact when the switch is in closedposition, a coil spring positioned within the U of the end contact forexerting axial pressure against the switch blade, a coil spring mountedupon each of the side contacts for exerting opposed. lateral pressureagainst the switch blade, a coil spring surrounding the pivot of theswitch blade for exerting radial pressure against said blade, and an armfor operating said switch 6 rigidly secured to the switch blade pivot inangular relationship to the switch blade and havin a remote controlconnected therewith.

JOHN E. DIGMAN. CARL S. DAVIS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 905,782 Barnum Dec. 1, 19081,911,739 Bangston May 30, 1933 15 1,950,194 Samad Mar. 6, 19342,347,030 Crabbs Apr. 18, 1944

